In all my years of flying SK (at peak 100+ flights/year) with hand luggage only, I have never ever once had it weighed, let alone been asked to check it in, when travelling with a rollaboard and a laptop bag. Granted, I am always in Business (or Plus intra-European), but the only time I came close was on a CR9 from MAN to CPH once, but being on a full-fare Plus ticket did the trick to make them go away..